a.In town of “S” after application by airplane of 5632 pounds of DDT in Diesel oil over a four month's period, there was no evidence of a lowered incidence of malaria among the residents as measured by splenic or blood positive cases. In fact, incidence of parasite positives, April 1946, increased practically 100 per cent over the incidence of April 1945 and was considerably higher than the comparison town of “N.C.”
b.In town of “L”, the boxes sprayed with 5 per cent DDT in kerosene and after “weathering” gave evidence of a lethal capacity for mosquitoes introduced into them and forced to rest on the sprayed walls. This lethal capacity reached 100 per cent mortality for mosquitoes confined in the boxes for five hours 129 days after having been sprayed. (The evidence of malaria, however, as measured by splenic and blood positives shows practically no alteration when compared with the comparison town or compared with the survey of 1945 performed in the same town.)
c.The town of “P” has shown a marked drop in malaria incidence as measured by blood findings both when compared with the comparison town and compared with its own survey performed in April last year.
d.The comparison town where no control was performed showed blood and splenic positive cases practically the same in April 1946 as in April 1945.
Colonel, M.C., A.U.S., Commandant, Army School of Malariology, APO 827, % Post-master, New Orleans, La.